Blackboard eraser



July 14, 1925. 1,545,961

M. R. KEENAN BLACKBOARD ERASER Filed Oct. 10, 1924 A A TTUR/VE PatentedJuly 14, 1925.

UNITED STATES PATENT OFFICE.

MADELINE B. KEENAN, OF BROOKLYN, NEW YORK.

BLACKBOARD ERASER.

Application filed October 10, 1924. Serial No. 742,781.

To all whom it may concern:

Be it known that I, MADELINE R. KEENAN, a citizen of the United States,residing at 6 1-5 10th Street, Brooklyn, in the county of Kings andState of New York, have invented new and useful Improvements in'Blackboard Erasers, of which the following is a specification.

The invention relates to ,erasers of the kind used in erasing chalk fromblackboards.

In school rooms where blackboards and chalk are used extensively it iswell known that quantities of chalk dust are thrown into the air by theuse of the ordinary blackboard erasers, and that this is detrimental tohealth, injurious to clothing and generally annoying and inconvenient.The draw back is, in fact, a serious one.

The object of the invention is to provide an eraser that will do awaywith these conditions. Means are provided for moistening the felt pad onthe eraser with a suitable liquid which will dissolve the chalk on theboard and thus eliminate any possibility of chalk dust flying about. Aparticular object is so to design the eraser that the pad may be quicklyand evenly charged with a desired amount of the liquid.

Further objects and features of the improved eraser will be brought outin the following specification and illustrated in the drawings forming apart thereof.

Referring to the drawings:

Fig. 1 is a longitudinal sectional view,

Fig. 2 is a cross sectional view, taken on the line 22 of Fig. 1, and

Fig. 3 is a detail perspective view of the member forming the partitionbetween the two compartments of the liquid receptacle.

The reference numeral 4 designates the body casing, made tight so as toserve as a liquid receptacle and provided with a handle 5 and a plug 6that may be removed for filling. The receptacle is preferably made inthe form of an oblong box, open at its front or under side, and having aflange 7 around the edges of this open side of which is secured bystitching 8, or other means, the eraser pad 9.

A plate 10 forming a partition is secured in the lower part of thecasing. This plate may be flanged as shown so that it may beconveniently secured in the casing by soldering, or otherwise. As shownin Figs. 1

and 2 this partition serves to divide the casing into two compartments,a large compartment or reservoir 11 and a small one 12 constituting acharging and distributing chamber substantially coextensive with thearea of the pad. The large compartment acts as a storage compartment andholds sufficient liquid to supply the eraser pad for some time. Thesmall compartment holds enough liquid to moisten the pad .for innnediateuse.

Means are provided for allowing the fluid to pass from the largecompartment to the small one and in the present embodiment of theinvention comprise a valve member 13 which is normally held seated onthe valve seat 14, formed in the partition 10, by a spring 15. When thevalve 13 is unseated the liquid will be free to flow into the smallercompartment.

Means are provided in the small compartment to insure the liquid beingdistributed or spread over the eraser pad so that all parts of it willbe moistened. This means comprises a perforated plate 16 which ismounted between the eraser pad and the partition. When the valve 13 isopened the fluid will enter the small compartment and pass through thefine perforations in the plate 16 and thence to the eraser pad. Afterusing the eraser a few times one will easily be able to determine howlong the valve 13 should be held open to moisten the felt padsufficiently.

Means are provided for operating the valve 13 and at the same timeallowing air to enter the large compartment while the liquid is flowinginto the small compartment. The valve 13 has a valve stem 17 in thereservoir and this valve stem has on its upper end a push buttom 18 forforcing the valve 13 to open. This member 18 in reality constitutesanother valve. As the memher 18 is pushed down to unseat the valve 20 isconfined between the member 18 and a shoulder or collar 21 on the valvestem. This spring 20 might be eliminated if it were desired to make thepartition wall 10 flexible enough so that the heavy spring 15 wouldinsure both valves being seated;

Bars 22 supported at their ends in the flange of the plate 10 extendacross the subchamber of the compartment 12; which is below theperforated plate 16. These bars form a grid intervening directly betweenthe perforated plate and-the'back oi the pad, the function of which isto preserve this sub-chamber by holding the pad away from theplate, asclearly seen in Fig. 1.

A preferred embodiment of the invention has been described andillustrated andit is to be understood that numerous changes may be madein the details of construction without departing from the spirit of theinvent-ion as embodied in the claim.

What I desire to claim as new is:

A blackboard eraser comprising an oblong a bozqa' pad securedtotlielow'er edge's thereof, a partition wall extending across the lowerpart of the box adjacent said pad 'to' form a large" reservoircompartment charging compartinent betWeen the valvedp'a-rt-ition and thepad, and means spacing;- the pad from said perforated plate, said meanscomprising bars forming a grid intervening, between said perforatedplate and the back of the pad and preserving a subohamber of thedistributing compartment between'saidplate-and pad; H MADELINE R.KEENALN.

